Alan Gaffney admits Saints were 'dominated' during a difficult second half at The Rec.
The coaching consultant saw his side suffer a 32-9 defeat to Bath, who conceded just three points after the break.
The home side scored two tries after the interval, adding to Matt Banahan's effort on the brink of the break.
And Saints were eventually made to suffer on a night that had started so well, with two Piers Francis penalties putting them 6-0 up.
After the break, it was one-way traffic towards the Northampton line, with Nick Auterac and Ross Batty registering for Bath.
And Gaffney said: "We were dominated.
"They only scored two tries in the second half and we were pretty fortunate it was only the two with the amount of possession they had.
"It wasn't the fact they had possession, it was the fact we conceded so much possession to them beyond what they had themselves.
"We're not that good a side to concede that much possession to sides who are as clinical as Bath were tonight.
"They played a pretty simple game and it was a game we just didn't handle."
On the overall display, Gaffney said: "We started well and in the first half we were pretty good.
"To be down 16-6 at half-time probably wasn't indicative of the game and what had happened.
"But in the second half we didn't have much ball, we turned over a lot of lineouts and we tried to make the impossible pass.
"Bath just had too much possession, they're a big side and they just brought the game to us.
"We didn't control the areas of the pitch we wanted to control and we've got to get better in that area."
Banahan's score came with the clock having hit 40.
Saints tried to attack from halfway, but the ball came loose and a kick ahead found Banahan, who picked up and raced in for a crucial score.
"It wasn't the play for that part of the pitch and that part of the game," Gaffney said.
"The execution was very poor.
"They are little areas we've got to address and we've got to understand that wasn't the play to be playing there.
"I'm not going to take the flair out of the players - I never have and I never will. If they think it's on, it's on.
"We've got to let them examine that and ask whether that was really the good option at that time.
"We've got get ourselves around the paddock better, we've got to play in the right areas of the pitch and we're not doing that at the moment.
"Our kicking game was just not up to scratch."